Lifting magnet



Patented July l, 1924.

UNITED STATES PATENT OFFICE.

BERNHARD E. FERNOW, JR., O'F MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUT- LER-HAMMER MFG. CO.. F MILWAUKEE, WISCONSIN, A CORPORATION 0F WIS- GONSIN.

LIFTING MAGNET.

Application led February 12, 1920. Serial No. 358,294.

To all whom t may concern.'

Be it known that I, BERNHARD E. FERNow, Jr.. a citizen of the United States.y residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements, in Lifting Magnets, of which the following is a full, clear, concise.l and exact description. reference being had to the accompanying drawing., formingr a part of this specification.

This invention relates to lifting magnets.

Lifting magnets are commonly of annular form and provided with removable pole shoes which are utilized to support the coil or coils ofthe magnet, the latter being provided with a shield resting upon the pole shoes for support. and the present invention relates to improvements in such magnets.

One object of the invention is to provide such a magnet with means for supporting the coil shield independently of the pole shoes whereby the latter may be removed without disturbing the former.

Another object is to provide a magnet having a removable outer.x pole shoe of such construction as to minimize the strains on its securing means incident to blows imparted to such shoe.

Various other/objects and advantages will hereinafter appear.

" The accompanying drawing illustrates a lifting magnet embodying thevinvention and will now be described, it being understood that the embodiment illustrated is susceptible of modifications Vfalling within th scope of the appended claims.

In the drawing,

Figure 1 is a vertical sectional view of a lifting magnet embodying the invention; and,

' Figs. 2 and 3 are enlarged detail views of certain of the parts shown in Fig. 1.

The lifting magnet illustrated comprises an annular magnet frame 1 provided with a cylindrical center pole 2 and an annular outer pole 3, acoil. unit 4 mounted in an annular recessy formed between said poles, an annular coil shield 5 for supporting and protecting said coil unit and pole shoes 6 and 7 secured to the lower ends of poles 2 and 3 respectively. The coil unit 4 comprises a plurality of windings 8 formed of strap --copper and insulated in the usual manner, a cylindrical magnetic core 9`bored to receive center pole 2 and an annular magnetic plate 10 secured to the upper end of said core.

Coil shield 5 is designed for mounting within the recess between poles 2 and 3 with its lower face in substantially iush relation with the lower ends of said poles. The same is provided with an upwardly extend ing peripheralflange 11 designed to t Within a counterbore 12 in the lower end of pole 3 and the center opening thereof is designed to receive the lower end of core 9 which is of reduced diameter to provide an annular shoulder 13 for overlapping the inner edge of said shield. Flange 11 of said shield is formed to provide a cylindrical surface 14 and a circumferential shoulder 15 and the lower face thereof is provided with radial reinforcing ribs 16.

Coil shield 5 is secured to the magnet frame 1 by a split ring 17 expanded Within a groove 18 adjacent the lower end of pole 3 and having its upper face in engagement with shoulder 15 of coil shield 5. Ring 17 is rectangular in cross section and when expanded in groove 18 has its ends separated as shown in Fig. 3. To prevent contraction of said ring a spacing member 19 is inserted between the ends thereof, said spacing member being held in place by a rectangular key 20 driven between the same and the cylindrical surface 14 of coil shield 5. The inner face of spac-ing member 19 is provided with a groove 21 to receive key 20 and one end of said key is provided with a bent portionl22 to abut the end of spacing member 19 while the other end of said key is provided with a tapered portion 23 which is bent outwardly after insertion of the key to hold the same in place. i

Inner pole shoe 6 is secured to the magnet frame 1 by bolts 24 passing through said frame and said shoe and having their heads countersunk in the lower face of the latter. The outer diameter of pole shoe 6 is such that `the same slightly overlaps the inner edge of coil shield 5 and the upper face thereof is shouldered to fit within a counterbore 25 in pole 2.

Outer pole shoe 7 is of annular form and is secured to the magnet frame 1 by bolts 26 having their heads countersunk in the lower face of said shoe and extending through the same and through an outwardly extending soY peripheral flange 27 on the lower end of pole 3. Flange 27 has its lower face odset with respect"V to theend of' outer pole 3 to provide'a cylindrical surface 28 for a purpose hereinafter set forth and pole shoe. 7 is. 'coun'terbored to receive said cylindrical surface 28 and also the outer surface `of flange 27. The inner diameter of pole shoe 7 is suchthat the same overlaps the lower face of coil shield and the outer diameter of said shoe is such that a substantial amount of metal thereof extends outwardly beyond the periphery of flange 27. This construction of the shoe 7 tends to prevent blows `imparted to the periphery thereof fromdistorting the same in such a manner as to strain or injure the securing bolts 26.

Under such blows the metal in the periphery Of said pole shoe Hows freely in an axial direction while the metal in the vicinity of the bolts 26 is unaffected by such blows.

Vi'th. the parts arranged as above described the inner and outer pole` shoes 5 and 7 can be readily removed for replacement or repair-f without disturbing the coil shield Also, upon removal vof said shoes the coil shield can also be readily removed for inspection or repair of coil unit 4;. By straightening the tapered portion 23 of key 20, said key can be removed to release the spacing member 19 and upon removal of 4said member vthe ring can be contracted to release coil shield 5. To facilitate removal ofspacing member 19 and contraction. of ring 17 a series-of tapped holes 30 are provided eXt-ending from the cylindrical surface 28 into the bottom of groove 18. By lscrewingl studs into these holes the spacing member 19 can be readily removed and ring 17 can then be forced inwardly at a plurality of points to contract the same.

rPhe coil unit is sealed within the magnet frame .1 and for this purpose the groove 18 is made sufliciently large to accommodate a packing 31 above ring 17. Packing is also inserted between the end of core 9 and shield Sandthe lower end of pole 2 is reduced in i' vdianfieter to permit insertion of packing between the same and core 9. The magnet is providedwith the usual armored leads 32 connected to the coils of the unit within a housing 33 on the upper face of the magnet frame.` The magnet frame is `also provided on its upper face 'with the usual suspension lugs 34 and on its periphery with the usual oo rrugations 35 .arrangedbetween bolts'26 and extending aXially'of the magnet case.

'i `vVVhatl claim'as new ,anddesire to secure by Letters Patent is:

"1'."ln` a vlifting magnet, in combination, a magnet frame having concentric inner'fand outer: poles', an energizing 'coil varranged 'within the annular channel between said poles, a YI'Jrotecting plate for said 'coil readily for the act-ive faces of said inner and outer poles, said shoes having shoulders underlyl able pole shoes for the active faces of said inner and outer poles, said shoes having shoulders underlying said protecting plate and means for `detachably securing said plate to said frame independently of said shoes for support of said member and coil.

3, In alifting magnet, the ycombination with a winding, of a magnet framehaving an annular channel 1n its'bottom face to receive said windin one of the side` walls of f'f said channel having a circumferential shoulderadjacent its lower edge, an annular coil shield located within said channel for supporting and protecting said winding, said coil shield having a surface on its underside adjacent said shoulder and a'fastening member for said coil shield interposedbetween said face and said shoulder. j i

4. In a lifting magnet, in combination, an energizing winding, a magnet framehaving lOO inner and outer poles and an annular c han.-

nel between said poles to receive said: winding, one of the side walls of said channel having a circumferential shoulder adjacent its lower edge, Van annular coil'shi'eld located within said channel to hold said winding in place, said coilshieldliaving a surfacel on" its under side adjacent said shoulder and a split Vring interposed between said shoulder and said surface to lock said coil shield to said magnet frame.

5. In a lifting magnet, in combination, an energizing winding, a magnet frame'having inner and outer poles and an annular'recess between said poles to receive saidwinding,

the inner wall of said outer pole having' 'a circumferential groove adjacent its lower edge, a coil shield arranged between'said poles for supporting said winding and protecting lthesame, said coil'shield having a face on its under side adjacent said groove I andfa split ring4 expanded within said groove and engaging said face to'lock said coil shield to said magnet frame. 6. In a lifting magnet, in combination, an energizing'winding, a magnet frame'ha'ving `inner and outer poles and annular recess between said poles to receive' said winding, the inner'wall Aof said outer pole having" a circumferential "groove "adjacent its lower edge, a coil shield arranged between said poles for supporting said winding and protecting the same, said coil shield having a face on its under side adjacent said groove, a split ring expanded within said groove and engaging said face to lock said coil shield to said magnet frame and means for preventing contraction of said ring to thereby lock the same within said groove.

7. In a lifting magnet, in combination, an energizing winding, a magnet frame having inner and outer poles and an annular recess between said poles to receive said winding, the inner wall of said outer poles having a circumferential groove adjacent its lower edge, a coil shield arranged between said poles for supporting said winding and protecting the same, said coil shield having a face onits under side adjacent said groove, a split ring expanded within said groove and engaging said face to lock said coil shield lto said magnet frame, a spacing member within said groove and interposed between the ends of said ring to prevent contraction thereof and a key inserted between said member Vfand a surface on said coil shield to lock said spacing member within said groove.

8. In a lifting magnet, in combination, a, magnet frame having a cylindrical center pole and an annular outer pole surrounding said center pole, a winding mounted in the annular space formed between said poles and pole shoes removably secured to the bottom faces of both of said poles, the pole shoe on the outer pole projecting outwardly beyond the periphery of said magnet frame.

9. In a lifting magnet, in combination, a

circular magnet frame having a cylindrical center pole and an annular outer pole surrounding said center pole, a winding mounted in an annular recess formed between said poles and a removable pole shoe on the active face of said outer pole, said pole shoe being of larger diameter than said magnet frame and being counterbored to receive the lower end of said outer pole whereby the metal in the periphery of said pole shoe is free to flow axially upon subjection of the same to blows.

l0. In a lifting magnet, in combination, a circular magnet frame having a cylindrical center pole and an annular outer pole surrounding said center pole and provided with an outwardly projecting peripheral flange on its lower end, a winding mounted in an annular recess formed between said poles and removable pole shoes on the active faces of both of said poles, the pole shoe on the outer pole being of larger diameter than said flange and being counterbored to receive the same.

ll. In a lifting magnet, in combination, a winding, a circular magnetic frame therefor having a center pole and a concentric outer pole, a removable pole shoe for said outer pole and bolts passing through said pole shoe and portions of said outer pole to secure the former to the latter, said pole shoe being of greater diameter than said outer pole and having a flange extending parallel to said bolts to surround the end of said outer pole.

In witness whereof, I have hereunto subscribed my name.

BERNHARD E. FERNOW, J 1L 

